Various kinds of recording materials containing microcapsules have heretofore been known.
For instance, Japanese Patent Publication No. 14344/67 (corresponding to U.S. Pat. No. 3,219,446) illustrates an image-transfer method wherein a photographic material sheet having a lot of small drops of fluids which may become non-fluid when irradiated to light is imagewise exposed to light and the exposed sheet is adhered to an image-receiving sheet, and a pressure is imparted to the whole of the laminated sheets whereby the image formed in accordance with the light-exposure is transferred on the image-receiving sheet.
Japanese Patent Application (OPI) No. 89915/52 (the term "OPI" as used herein means an "unexamined published patent application) illustrates a method for formation of an image, where one component of two component-type heat-sensitive coloring substances and a photopolymerizable monomer are encapsulated in microcapsules and the other component of the heat-sensitive coloring substances is blended with the microcapsules, and the resulting mixture is coated on a support sheet to obtain a photographic material sheet, and then, after the photographic material sheet is imagewise exposed to light thereby to harden the microcapsules in the exposed part, the whole surface of the photographic material sheet is heated to color the non-exposed part only, whereby a desired image is formed on the sheet.
Japanese Patent Application (OPI) Nos. 124343/82, 179836/82, and 197538/82 describe a method for formation of an image where microcapsules containing a vinyl compound, a photopolymerization initiator, and a dye-precursor are used, and the photographic material containing the components is pressed over the whole surface thereof, after having been imagewise exposed to light, to form a color image on the material, and this method does not require any heating step.
Japanese Patent Publication No. 20852/79 (corresponding to U.S. Pat. No. 3,700,439) describes an image-formation method using a photosensitive substance of Michler's ketone as encapsulated.
U.S. Pat. No. 3,072,481 illustrates a so-called light-sensitive and pressure-sensitive image-formation method, where a photosensitive substance which may easily be converted into a colored state when liquid, but is non-photosensitive when solid, is encapsulated, and the layer containing the encapsulated substance is imagewise exposed to light and thereafter, the capsules are ruptured under pressure to remove the solvent contained therein by evaporation, to thereby form an image on the layer.
Various means for the formation of images by the use of microcapsules have heretofore been known, as mentioned above. These conventional means, however, are defective in that the sensitivity to light is low in every case, and especially the sensitivity to green light or red light is extremely low. In addition, if the light-sensitivity is to be elevated in the conventional means, the preservation-stability is to become lowered on the other hand, which is another defect.
Regarding the formation of images by the use of a silver halide as a light sensor, various photographic materials except so-called conventional photographic materials have been known.
For instance, British Patent 866,631 describes a method for the direct photopolymerization by the use of a silver halide as a catalyst. In this method, it is considered that the product formed by the photolysis of the silver halide used will act as a catalyst in the polymerization, and the sensitivity is not so high as in the case for reduction of silver halides in a conventional development.
Belgian Patent 642,477 describes a method for the formation of images where light-exposed silver halide particles are developed with a conventional developer and thereafter polymerizable monomers are polymerized in the presence of the formed silver images or the non-reacted silver halides, which act as a catalyst in the polymerization, to form polymeric compounds in the form of images. This method is, however, defective in that it requires some complicated operations.
Japanese Patent Publication Nos. 11149/70, 20741/72, 10697/74, 138632/82, and 169143/83 describe a method for the formation of images in which light-exposed silver halides are developed with a reducing agent, whereupon co-existing vinyl compounds are begun to be polymerized simultaneously with the oxidation of the reducing agent to form polymeric substances in the form of images. This method is, however, also defective in that it requires a development step with liquids.
As mentioned above, various means for the formation of images by the use of silver halides as a light sensor have heretofore been known, all of which are, however, somewhat defective in that the sensitivity is low and that some complicated development steps are required.